This application claims the benefit of Swedish Patent Application No. 0004276-2, filed on Nov. 22, 2000.
The present invention relates to a connection member according to the introductory portion of claim 1.
Electric power plant equipment comprises cabinets with devices for converting or transforming electrical power. The devices within the cabinet for converting electrical power can be so-called current rectifier devices.
In case of using large sets of cabinets or modules for converting electrical power, a plurality of cabinets or modules of standard model with similar outer measurement, are connected to each other for making a functional unit. Each cabinet comprises bus bars for internal distribution of electric current to the devices within the cabinets. The bus bars of each cabinet or module are connected to each other via a connection member for providing an electrical contact between the cabinets. The connection members are consequently mountable between the bus bars of the cabinets for making an electrical connection between the electric power devices in respective cabinet. The cabinets can be placed side by side alternatively with their rear sides oriented towards each other.
In some cases, the connection member has to be coarse for carrying a large electric current between the bus bars of respective cabinet. The electric current can be up to 1800 ampere or higher. Connection members can also be designed for electric current below 1800 ampere. A connection member according to prior art is formed as a short and stiff homogenous stick made of copper.
A connection member is made of a plurality of flexible cables, for example six copper cables of 150 mm2 area each. These connection members are also stiff due to their short length. This means that the alignment and the positioning of the cabinets must be precise for making an easy mounting of the connection member between the bus bars of respective cabinet. It is complicated and difficult to achieve desired positioning of the cabinets, using a connection member according to known technique.
A connection member is made flexible. The connection member consists of a plurality of strips made of copper, each 1xc3x9750 mm in its cross section. Other connection members consist of strips with other dimensions, for example 1xc3x9725 mm. The strips are assembled together forming a package. Each strip slip on the adjacent strip when the package is bent. The construction is complicated and is made of several parts. The construction can only be bent in one specific direction.
Known connection members, used for electrical connection between electric power distribution modules, suffer from the disadvantages that they are complicated and expensive to produce and mount. Known flexible connection members are also difficult to mount since these connection members have a spring back action ability. They are also bulky.
These problems have been solved by a connection member as initially defined, which is characterized in that the intermediate portion is made so flexible that the relative positions of the first and second joining end portions can be adjusted to a second relative status by means of plastic deformation of the intermediate portion.
Hereby is achieved that the connection member according to the present invention will be mountable between two cabinets without any spring back action. A spring back action of the connection member would complicate the mounting of the connection member to the bars of the adjacent placed cabinets. The connection member according to the present invention means also that it is stiff in a first relative status, whereby it will be easy to assembly two cabinets to each other.
Further solutions regarding objects and features of the present invention are disclosed in the following claims.
Suitably, at least one of the joining end portions and the intermediate portion are made of the same material and in one piece. Hereby the connection member will be uncomplicated and less expensive to produce than prior art members.
Preferably, at least one of the joining end portions is made of a different material than the intermediate portion. Hereby the end portions can be arranged detachable and made of different material. This is advantageously when a set of intermediate portions of different length or thickness is used in a standard system. Assembly personnel can hereby replace a joining end portion designed with a first characteristic, to a joining end portion with different characteristic, without dismounting the entire connection member.
Suitably, the first and second joining end portions can be adjusted by hand to the second relative status. Hereby the assembly personnel can bend the connection member to join both bus bars of the cabinet without any support of tools. This will make the mounting uncomplicated.
Preferably, the intermediate portion comprises soft-annealed material for making the intermediate portion flexible. Hereby the manufacture of the connection member is less expensive than prior art and less complicated.
Suitably, at least one of the joining end portions comprises cold worked material. Hereby a joining section, made of a material with a higher degree of hardness tan the material of said intermediate portion, is achieved by means of an uncomplicated manufacture method. The achieved hardness of a part of the joining end portions being in contact with the bus bars, has the effect that the fastening will be solid. The hardness of the material of these parts is so high, that a nut drawn at a threaded pin or a fastening clamp pressing against the part will not fleet thereupon and therefore be sufficient tightened. By means of cold working, the connection member can be made in one piece in a economically advantageous manner.
Preferably, at least one of the joining end portions comprises junction means for fastening the connection member to a bus bar of the electric power distribution module. Hereby a fastening of the connection member can be achieved In a suitable way onto the bus bar of the cabinet. The junction can be achieved by means of screws, a bolt and nut assembly etc.
Suitably, the connection member essentially has a circular cross-section area for making the intermediate portion flexible in all directions divergent from a central line essentially defined by the longitudinal direction of the intermediate portion when the joining end portions are in the first relative status. Hereby the cabinets can be mounted to each other without the necessity to adjust them in a precise manner depending on the fitting of the connection member. Since the assembly personnel do not have to spend time wasting work on adjusting the cabinets to each other in an exact conjunction depending on a stiff or back spring acting connection member according to known technique, the procedure to connect the two cabinets to each other will take less time than what is normal according to known technique. The adjustment is though possible in all directions of a plane corresponding to the sides of the cabinets being placed toward each other. Since the connection member is flexible in all directions of said plane, the cabinets can be adjusted in any desirable positions relatively each other after that the connection member according to the invention is fastened. This also means that the bus bar of each cabinet do not need to have an exact normative distance to said side of each specific cabinet or an exact level over a floor on which the cabinets are standing.
Preferably, the connection member essentially has a rectangular cross-section area for making the intermediate portion essentially flexible in the directions congruent to a plane extending transverse the cross-section area and parallel to the shorter side of the rectangle defined by the rectangular cross-section. Hereby the assembly personnel do not have to make an effort to adjust the cabinets to each other in an exact conjunction during mounting. This will also reduce the mounting cost.
Suitably, said connection member has its prolongation formed as a Z and is made of copper. Hereby a folding effect is provided. When the both joining end portions of the connection member are pulled from or pushed towards each other, the Z-formed prolongation implies that the connection member will act like an expansion joint. This means that the mounting of the connection member to the respective bus bars of two cabinets will be less complicated and less expensive. Since the assembly personnel do not have to spend timewasting work to adjust the cabinets to each other in an exact conjunction, especially an adjustment in the longitudinal direction of the connection member, the procedure to connect the two cabinets to each other will take less time than what is normal according to known technique.